[RFC PATCH v1 1/4] vfio/type1: Add a bitmap to track IOPF mapped pages

[Shenming Lu <lushenming@huawei.com>]

When IOPF enabled, the pages are pinned and mapped on demand, we add
a bitmap to track them.

Signed-off-by: Shenming Lu <lushenming@huawei.com>
---
 drivers/vfio/vfio_iommu_type1.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 0b4dedaa9128..f1d4de5ab094 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -95,6 +95,7 @@ struct vfio_dma {
 	struct task_struct	*task;
 	struct rb_root		pfn_list;	/* Ex-user pinned pfn list */
 	unsigned long		*bitmap;
+	unsigned long		*iommu_mapped_bitmap;	/* IOPF mapped bitmap */
 };
 
 struct vfio_group {
@@ -143,6 +144,8 @@ struct vfio_regions {
 #define DIRTY_BITMAP_PAGES_MAX	 ((u64)INT_MAX)
 #define DIRTY_BITMAP_SIZE_MAX	 DIRTY_BITMAP_BYTES(DIRTY_BITMAP_PAGES_MAX)
 
+#define IOMMU_MAPPED_BITMAP_BYTES(n) DIRTY_BITMAP_BYTES(n)
+
 static int put_pfn(unsigned long pfn, int prot);
 
 static struct vfio_group *vfio_iommu_find_iommu_group(struct vfio_iommu *iommu,
@@ -949,6 +952,7 @@ static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
 	vfio_unlink_dma(iommu, dma);
 	put_task_struct(dma->task);
 	vfio_dma_bitmap_free(dma);
+	kfree(dma->iommu_mapped_bitmap);
 	kfree(dma);
 	iommu->dma_avail++;
 }
@@ -1354,6 +1358,14 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
 		goto out_unlock;
 	}
 
+	dma->iommu_mapped_bitmap = kvzalloc(IOMMU_MAPPED_BITMAP_BYTES(size / PAGE_SIZE),
+					    GFP_KERNEL);
+	if (!dma->iommu_mapped_bitmap) {
+		ret = -ENOMEM;
+		kfree(dma);
+		goto out_unlock;
+	}
+
 	iommu->dma_avail--;
 	dma->iova = iova;
 	dma->vaddr = vaddr;
-- 
2.19.1